Improvement in rqtary blowers



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@with wI'IlLIAM, e. IIYNDMAN, or leINoIN'NATI, oIIIo.

' u Letters Patent No. 106,165, dated August 9, 1870.

IMPROVEMENT IN RQTRY BLCWERS.

The Schedule referred to in these LettersPatene and making part of the same.

I, Waerme. Hemmer, `of cincinnati, in the county of HamlltonaudState of Ohio, have invented certainImprovnnents.in RotaryBlowers, of which the following is a specicatiom Nature and Gbjects of the I iweation. The nature of my in vention consists- First, in. a blower-case in two parts, the interior surface of which is rendered trueand accurate by a coating of bees-wax and asphaltum, bees-wax and resin, sulphur, or brimstone, or any/ similar substance which may be rendered plastic by'artiiicial heat, and that is not a metal. The object in making the case in two parts isto give additional strength, to save labor and material in its construction, and to enable the removal vof the upper part without Idisarranging the pistons or the lowerpart.

Second, thenature of my invention also consists inthe construction `of skeleton pistons, with blades or wings, of equal length, extending from the hub which forms the piston, having grooves formed by.plastcr of Paris, with which the skeletoupistonsare finished, in the hub iu which the outer edge of the blades t alternately as they revolve. The object of-thus constluctingpistous and blades is to make the blower comparatively air-tight, and to ei'ect a saving'of metal. f

Dcscmptionof Accompanying Dra/wing. 'Figure 1 is a longitudinal-vertical section ot' the blower, through the linea a of fig. 2. Figurej2 is'a vertical cross-section of fig. 1, through the line a: x.. i

Y General Description. is the case, the 'circles of which correspond with the circumference ot thepistons. A

B B lare the pistons. C O are the'blades or wings of the pistons. D D are the grooves in which the blades or wings revolve, the circle of which corresponds to the ends of `the bladeswhile both are in motion.

The two parts of the case are joined on the line of the axial plane through the journal-boxes, the seat of the `journal being uponl the lower case, and the caps upon theupper one, anda lip or flange can be made to project upon each side andV end,` fastened by holts,`similar to the ordinary manner of making journal-boxes. n The upper section of the case is cast iu one piece, withoutthe ordinare7 guards or ledges usedto hold a lining, such as is set forth in the patent of P.H. and F. M.Roots, dated .August 1'1, 1868.

The case is rendered true and accurate without machiue-work, bythe use of a thin coating of' beeswax and asphaltum, or beeswax and resin,*or brimstone. -This can beapplied in the following manner:

I construct a cylindcr of the circumference of the blades of the pistons used in the case, with proper jonrnal-bearing upon the shaft, and apply the material for lining when melted, and revolve the cylinders, f

'to render all parts of the case true.

This lining has many advantages over all othersY before used, it being tougher and more durable than plaster of Paris, which oxydizes' the iron, and cools -much more rapidly than plastic-sapplied in a cold condition, which harden slowly, and being much cheaper than molten lining.

Another and more important advantage of' 'using this material is, no lips or guards arenecessary upon the case, and a very thin coating will be effectual.

Thelower case is madein the ordinary rectangular shape. The seat o t' the journal-boxes and legs to Vfasten down are usually cast on the case, as shown in fig. 2, and open upon thebottom for a free admission of air.

The abutting pistons B B aredesigned to revolve each upon journal-bearings I? P', and are relatively arranged within the respective are ot the case, as shown.

- Goucavities D D are formed to coliform to the arc of the circle each blade describes iuits abut-ting the concavity between the blades upon the opposite piston. The contracting or abutting surfaces of the blades and concavities should not. touch sufficiently to cause any appreciable amount of friction, but yet so near as to prevent escape oi' air.

The projecting shoulders E E are iron, cast on' the blades, and are locatedat thepoint where the concavities cease, so that they may overlap andform a y contracting surface, as seen at E, in iig. 2, and the cavities are formed by and filled with beesavaxvaud resin, vor other similar substances.

The pistons B, blades O, shafts H, and ledges or fianges E are cast in one piece, and trued or tted by ordinary machine-work to the case, and made to revolve in the bearings l P.

The cavities d' are filled with bees-wax and resin, and, while in a heated and 4plastic condition, the pis tous are slowly revolved, to form the desired shape ot' the concavities D, or they may be shaped by molds or` patterns,- the plaster being poured around them while in a liquid state.

Pistons made as described are much easier shaped or ittedto form facesl working air-tight, or nearly so,

andeifect a much greater saving of metal than when constructed in the ordinary manner.

I am aware blower-cascs have been made all cast.

in one piece, such `as are shown in the patents of P.

'H and F. M. Roots, ot' January 2land August 11,

1868. Ido not, therefore, claim a blower-case, broadly. I am also aware that plaster of Paris has been used `resin or brimstone, retained without the use of guards and ledges, all substantially as herein set forth.

2. The pistons B B, composed of the blades C C, guards E E, coneavities D D, with the lining d applied in :t liquid condition, wlrile heated, to form a, continuons contact of thev blade-surtees, all substantially as herein set forth. v

W. G. 'HYNDMAIL Witnessesz i Y E. E. Woon, EDWARD BOYD. 

